UDR7 Dynamic DNS using Namecheap

This procedure describes how to configure the Unifi Dream Router 7 Dynamic DNS service to periodically update A + Dynamic DNS Record router.dubravko.com at Namecheap DNS server with the public IP address of Primary (WAN1) interface.

Namecheap DNS Configuration

1. Enable Dynamic DNS in the Advanced DNS settings
2. Note the Dynamic DNS Password value, as it will be needed later
3. Add a new A + Dynamic DNS Record with the following details

Parameter	Value
Type	A + Dynamic DNS Record
Host	router
Value	1.1.1.1
TTL	Automatic

UDR7 Dynamic DNS Configuration

1. In the https://unifi.ui.com web console, navigate to Settings > Internet > Primary (WAN1)
2. Set the Advanced option to Manual
3. Under Dynamic DNS, click + Create New Dynamic DNS and set the following values

Parameter	Value
Service	namecheap
Hostname	router
Username	dubravko.com
Password	Paste the password noted during Namecheap DNS Configuration
Server	https://dynamicdns.park-your-domain.com/update?

Set up UDR7 periodic updates

When the UDR7 is behind a non-bridged telecom router, it cannot detect changes in its public IP address. This limitation prevents the automatic triggering of DDNS updates. To overcome this issue, you we can set up a cron job to periodically force DDNS updates. This involves editing the root crontab to add a line that runs the inadyn command at regular intervals, typically every five minutes.

This step is required only if your UDR7 is behind non-bridged telecom router. If the telecom router is set to bridge mode and the UDR7 is configured to connect to the Internet directly via a PPPoE connection, UDR7 will automatically detect each public IP change and trigger DynDNS update.

Detect inadyn configuration file name

The file /run/ddns-ethX-inadyn.conf is created by the UniFi Network Controller when you configure the Dynamic DNS service through the web UI. This configuration file contains the necessary settings for the inadyn DDNS client to update your Namecheap DDNS record. The filename may vary depending on which Ethernet interface is used for your WAN connection. It’s crucial to use the correct filename in your cron job to ensure proper DDNS updates.

To detect the proper file name for your configuration:

1. SSH into your UDR7 device
2. Navigate to the /run directory:

   cd /run
   

3. List DDNS configuration files:

   ls ddns-eth*-inadyn.conf
   

4. Note the exact filename (e.g., ddns-eth3-inadyn.conf)

Edit the Crontab

1. Open the root crontab for editing:

   sudo crontab -e
   

2. Add the following line to the crontab:

   # Namecheap DynDNS record update every 5 minutes
   */5 * * * * /usr/bin/inadyn -n -s -C -f /run/ddns-eth3-inadyn.conf -1 -l --foreground --force
   

Save the Crontab

1. Press Esc
2. Type :wq
3. Press Enter

Verify the Cron Job

1. Display the current crontab:

   sudo crontab -l
   

2. Confirm the new line is present and correctly formatted.

This configuration will execute the Dynamic DNS update every 5 minutes, ensuring your public IP address remains current with your Namecheap Dynamic DNS record.